Various inbred mouse strains exist which differ from one another with respect to certain behavioral characteristics. For example, C57BL/6 mice when given a choice between water and a 10% ethanol solution, prefer to drink the alcohol, while mice of the A strain prefer water under the same conditions. This project is aimed at the localization of the cell populations responsible for alcohol preference (and for come other behavioral traits, see below) by the use of chimeric mice. A series of chimeras will be made which combine cells from the C57BL/6 and A strains, and each chimera will be tested for alcohol preference. When the response to alcohol has been noted, each animal will be killed and the distribution of C57 and A cells within its body will be analyzed. When a series of chimeras has been analyzed for behavior and cell distribution, an attempt will be made to correlate behavior toward alcohol with the cellular composition of a given tissue. Thus it might be found that when the liver is composed of A cells the mouse always avoids alcohol, indicating that the physical difference between these two strains which gives rise to their behavioral difference lies in the liver. The same techniques will be used to locate the cell populations responsible for differences between the A and C57 strains in open field activity and cricket killing.